Comparing Arctic cod Gadus and known prey the hermit crab genus Pagurus.

How do the distributions of known predator and prey compare?

How do the distributions change with location, depth, and water temperature?

For this project:

1. Data from NOAA Alaskan Trawls will be merged and organized to maximize data from all parts of the Bering Sea.

2. Data will be filtered and chosen, then analyzed for graphical use

3. Visualizations will be made that display the distribution of the two species by location, water temperature and depth.

Imported library

A lot of packages were needed to complete this project:

1. tidyverse, using ggplot2, tidyr, and dplyr to organize data

2. rnaturalearth, rnaturalearthdata for world map data

3. ggmap, maps and mapdata for map data as well

4. rgeos and sf for error-fixing/ map holes

Data merged to maximize area of map

Trawls from The Aleutian Islands, North and East Bering Sea, the Bering Sea slope and the Gulf of Alaska all merged

Trawls taken at different years for different number of years, future work could be more accurate by making sure years match, could make time plots

Select data using tidyr and dplyr

• Separated scienticic name column into Genus and species columns
• Separated date-time column into date and time columns
• Select data relevent for current and furture anaylysis

Filtered out Pagurus and Gadus genuses

Two most common and known predator-prey relationship

trawl <- 
  trawlall %>% 
  separate('GENUS_SPECIES', c('GENUS','SPECIES'),'_', extra='drop') %>%
  separate('DATETIME', c('DATE','TIME'),'_', extra='drop') %>%
  select('LATITUDE','LONGITUDE','DATE','TIME','GENUS','SPECIES','BOT_DEPTH','BOT_TEMP', 'SURF_TEMP')

Pagurus <- 
  trawl %>% 
  filter(GENUS=='Pagurus')

Gadus <-
  trawl %>% 
  filter(GENUS=='Gadus')

trawl <- rbind(Gadus, Pagurus)

Map of Alaska with locations of trawls involing chosen genuses

Comparing surface and bottom temperatures

Distributions by depth

So what was the point?

Looking at the differeing distributions of predator and prey can tell us the differences in abundance and set baselines for future studies

If in the next 5 years, this data has change significantly, previous years can tell us what has changed about the environment

Questions? Comments?